Drilling bit



Aug. 6, 1940.

T. H. STANCLIFF 2,210,101

DRILLING BIT Filed Jan. 30, 1959 Pate edau amo i I g 2,210,101 I UNITED, STATES PATENT OFFICE I nnILunG m'r Thomas H. Stanclifl, Houston, Tex, assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application January 30, 1939, Serial No. 253,563

2 Claims. (01. 255'i1)' This invention relates to drilling bits, and parwelding I. Carried by the arms 6 either lnte-' ticularly that type of drilling bit known as a grally or otherwise as desired are sections of cross roller bit, wherein the cutting action is produced roller pins 8 and 9, the inner ends of which are by rollers which engage the formation with a adapted tobe positioned within the opening in rolling action and which have teeth thereon the bridge 5 and welded therein as shown at I0. 6 which dig into the formation as the rolling action Intermediate the ends of these shafts races are takes place. provided thereon for the roller bearings I l and I 2 The general object-of this invention is to prowhich are adapted to take the radial load on the vide such a drill bit in which the' cutter teeth cutters l3 and I4, and ball bearings l5 adapted 10 will be less apt to break off in use than those to take the end thrust from these cutters: It 10 heretofore employed. will be not'edthat each of the thrust ball bearings The present invention relates particularly to I5 is positioned to take end thrust in a radially. the formation of the teeth on roller cutters so outward direction only, but this is sumcient belocated that in use there is an end thrust exerted cause of the fact that this is the only substanthrough the teeth upon the cutters in the same tial thrust which occurs during the operation of direction substantially at all times. It has been the bit. customary in the past to form the teeth on these It will be seen that while the bit is in operation cutters in many instances in rows extending cirdue to the fact that the roller cutters l3 and i4 cumferentially with respect to the cutters. In do not have a true rolling action on the bottom some instances these rows are separate and in of the hole, there will constantly be a force ex- M other instances they form continuous spirals. erted on the cutters through the teeth l6 and I1 customarily such teeth have been formed with thereof tending to move these cutters radially their opposite sides disposed at equal angles to outwardly. This force likewise tends to break oil a line perpendicular to the axis of the rotation of these cutter teeth. In order to counteract this the cutter. Thus, although the teeth were tendency and to make the.teeth better able to as equally strong in both directions to resist a resist the outward thrust action exerted upon thrust action thereagainst, substantially all the them, this invention contemplates that the teeth thrust was in actual practice exerted in one shall have their opposite sides disposed at equal dir ction, angles not with respect to a line perpendicular It is an object of this invention, therefore, to to the axis of the cutter, as in my prior Patent 80 so form the teeth on a roller cutter of the type No. 1,998,793, dated April 23, 1935, but with reset forth that the teeth will be better able to spect to a line inclined toward the inner end take the thrust stresses imposed upon it during of the cutter. In the particular instance illusoperaticn. trated, the opposite sides of the teeth are dis- 5 In the drawing: posed at substantially equal angles with respect :6

The single figure illustrates a vertical cross to a line normal to the cutting surface of the section with parts shown in elevation, however, cutter. Because of the generally tapering f0rma-' illustrating. a bit having thereon cutters contion of the cutter toward the center of the bit, structed in accordance with this invention. this meansthat the'teeth are generally speaking 40 Referring more in detail to the drawing, the inclined toward the center of the bit rather than 4 numeral 1 indicates the body of the bit and the extending downwardly in a direction parallel to numeral 2 the threaded shank whereby the bit the axis of the bit. Furthermore, they extend is secured to the lower end of a drill stem. substantially at right angles to the solid portion Mounted upon opposing downwardly extending of the cutter on which they are carried. In the arms 3 are a pair of side roller cutters 4, only particular example illustrated, wherethe inclined 45 one of which is shown, which are adapted to cut angle between the inner and outer faces of each at the sides of the bottom of the hole. Extendtooth is 36, the inner face is disposed almost ing between the inner ends of the spindles on vertically, being only 6 from the vertical, while whichthese cutters 4 are carried is a bridge 5, the outer face is at 30 from the vertical, thus 5 the central portion of whichis formed with an serving to support the tooth against outward 60 opening for a purposepresently to be described. thrust.

Extending downwardly from opposed portions 7 It 'will readily be seen that by the construction of the head and at positions intermediate the setjorth a cutter has been produced having teeth arms 3 are a pair of additional arms 8, these which will be better able to resist the end thrust being in this instance joined to the head by imposed upon them during operation of the bit ll on said shaft, said cutters having cutting teeth' projecting therefrom and arranged in rows extending circumferentially with respect to said cutters, said teeth having opposite faces disposed at an angle to each other in such a manner that a plane passing through the apices of said cireumferentially arranged teeth and normal to said transverse cross roller shaft will divide said teeth into two portions, one portion which is the major portion lying radially outwardly of said normal plane, and the other portion which is the minor portion lying radially inwardly of said normal plane.

2. In a drill bit, a body, a cross roller shaft extending transversely of and normal to the vertical axis of said body, irusto-conical roller cutters rotatably mounted on said shaft with their smaller ends adjacent the vertical axis of Said body, said cutters having cutting teeth projecting therefrom and arranged in rowsextendlng circumferentially with respect to said cutters, said teeth having opposite faces disposed at an angle to each other in such a manner that a plane passing through the apices of said circumferentially arranged teeth and normal to said transverse cross roller shaft will divide said teeth into two portions, one portion which is the major portion lying radially outwardly of said normal plane, and the other portion which is the minor portion lying radially inwardly of said normal plane.

THOMAS H. STANCLIFF. 

